A hair treatment agent composition characteristically comprising a specific hydrophobically modified polyether urethane and cationic surfactant.The hair treatment agent composition of the present invention provides has good temperature stability in terms of the viscosity, exhibits superior fluid flow characteristics, achieves smoothness and ease of arranging the hair after drying, and gives a superior sensation during use.A cleaning agent composition characteristically comprising a specific hydrophobically modified polyether urethane and anionic surfactant and/or ampholytic surfactant.The cleaning agent composition of the present invention has superior viscosity and is superior in terms of foam formation as well as foam durability and feels refreshing without a slimy sensation after rinsing-off.